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' April 14, 1925. 1,533,729

s. EHRHA'RDT TYPEPRIN'HNG TELEGRAPH Filed on. 26, 1920 Patented Apr. 14, 1925.

UNITED STATES ERWIN EHBHARDT, OF HEBMSDORF, NEAR BERLIN, GERMANY, ASSIGNOR '10 SIEMENS & HALSKE, AKTIENGESELLSCHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY,

A GERMAN CORPORATION.

PATENT OFFICE.

TYPEPRIN TING TELEGRAPH.

Serial No. 419,779.

(GRANTED UNDER. THE PROVISIONS OF THE ACT OF MARCH 3, 1921. 41 STAT. L., 1313.)

."l '0 all whom. it may concern:

Be it known that I, ERWIN EHRHARDT, a citizen of the German Empire, residing at Hermsdorf, near Berlin, Germany, have invented certain new and useful Improvements in Typeprinting Telegraphs, (for which I have iiled application in Germany, Dec. 16, 1918), of which the following is a specification.

My invention relates to receivers for typeprinting telegraphs, especially of the class in which the signal to be printed is transmitted by a combination of a plurality of impulses succeedingeach other in point of time. Devices'of this kind have been employed in which two groups of relays generally polarized (which, as regards number correspond to the number of elements composing a signal), are alternately connected to the line across the commutator.

of the receiver by a switch device. In this case the relays of one group are set to correspond to the incoming signal, while the circuit of the printing electro-magnet, which is closed at the combination commuta tor flows across the relay armatures of the other group.

It has been further proposed in the prior art to connect two groups of condensers alternatively to the line by means of a switching device whereby the number of the individual condensers is equal to the number of individual current impulses of which a signal is composed. In this case one group of condensers is charged while the other is discharged by way of selective relays which control the operating of the printing mag net. In this arrangement furthermore polarized change-over relays are necessary which control the discharge circuit of the condensers. This arrangement has the disadvantage that it requires twogroups oi. condensers and that the polarized changeover relays constitute comparatively sensitive mechanisms.

In accordance with my invention, one of these relay groups may be omitted and the commutator simplified, by providing a condenser and a relay for each element of the signal, said condenser and relay being temporarily connected by the commutator device in such a manner that the condensers, charged as a result of the impulses in the line current, will transmit the charging current across their relays. The period for the discharge of the condensers depends upon the kind of typeprinting telegraph employed. Thus, for example, in the case of simple type telegraphs, the discharge must be eiiected in the interval between the reception of the two succeeding signals in order to secure the uninterrupted transmission of signals. On the other hand, in the case of multiplex telegraphs, operating intermittently, the discharge of a group of condensers may, theoretically speaking, be effected during the entire period during which the incoming signals are stored up by the other groups. In practice it will however be found expedient even in the case of multiplex telegraphs, to cause the discharge to take place immediately after the condensers have been charged up, in order to enable the signal to be printed, it possible, directly after it has been received.

The condensers are suitably charged by impulses of different polarity, so that their discharge currents will set the armatures of polarized relays in different contact positions.

The use of condensers in connection with. the receivers of type-printing telegraphs is well known. They are used such that they are charged by the line currents, while their discharge directly or indirectly excites the printing magnet. One of the novel features of the improved device over the old devices resides in the peculiar combination of condensers and relays, for by these means the possibility is given of reducing, for a certain total number of signals, the number of individual elements representing a single signal, and thus aliording the additional possibility of utilizing the line to an essentially better degree.

In the accompanying drawings forming a part of this specification, a structure em bodying the features of my invention is clearly illustrated partly in perspective, partly in diagram.

In the drawings S S and S indicate stationary segment rings; the ring S acting as receiver. Let it be assumed that each signal is composed of only two impulses, so that, in all, four different signals enter into consideration represented by the following combination of impulses; viz.: Each signal being composed of two impulses, the ring S is likewise provided with only two conducting segments 5 and 8 These are permanently in contact with earthed condensers 7: and Z0 respectively. A brush b insulatingly fixed to a shaft '20, glides across the ring S The shaft to is rotated by a motor M, running synchronously with the transmitter (not shown) of the transmitting station. The brush 6 is connected, by means of a slip ring contact (4 either directly or else across a relay (not shown) with the line L. hile the brush Z) passes successively across the contacts 8 and 8 say, in the direction indicated by the arrow, the condensers 7c andv k are charged. Of the two impulses successively arriving over the line L, during one revolution of the brush the first passes across the contact .9 and the condenser 7. to the earth E, and the second across the contact a and the condenser is likewise to the earth At the same time, the condensers are charged in accordance with the direction of current of the impulses. This what is termed storing the signals.

The work of translating thesignal thus stored up into a form suitable to produce the print is composed of two operations. The translating device is primarily adjusted to the signal inquestion, and only then the signal is printed. This operation is effected in the following manner: On the shaft n: are mounted two drums t 6 of an insulating material, each provided with an axially disposed metal strip m and m respectively. Two pairs of brushes 0 0" contact each in axial alinement with said drums in such manner as to be bridged from time to time by the metal strips 012 and m respectively. Vhile the brush 6 glides across the segments s 8 the brush pairs 0, c are in contact with the insulated portions of the drums t t Only when the brush Z1 passes over the insulated port-ion n. of the ring S hence in the interval between the reception of the two signals, are the brush pairs 0 0 connected by their respective metal strips m m The drums t 5' having assumed the position indicated, the condenser 731 discharges across a relay R and condenser k across the relay R R and R represent polarized, neutrally adjusted relays, so that their armatures f and r may be operated according to the direction taken by the condenser discharge current. Since each armature may assume two different positions for contact, there .8 and S Across these contacts pass the brushes Z) and 7), both of which are fixed to the shaft to and are connected with each other by means of a conductor 0 passing through a longitudinal bore of the shaft to. lVhile the brushes 6 b glide over the segments of rings S and S they close the circuit of the printing'magnet D, while in a position dependent upon that of the relay a-rniatures r and 7-", whereby the magnet D is energized, so that its armature 9, carrying a printing hammer 71 is caused to strike against the tape P and the typewheel T, which latter is likewise mounted on the shaft 10. In the structurev described andshown four types are fixed to the circumference of the type wheel as an example.

The operation of translating into print a signal stored up by the condensers k and 71?, may be described in detail as follows:

Let it be assumed the impulse combination has been transi'nitted across the main L. In that event the condenser is charged positively and condenser negatively relatively to the earth. While the brushes b", I)? pass across the insulated sections a of the segment rings S S S, the condensers 7: and [c discharge across the relays R and It respectively, which latter are thus enabled to throw their armatures into the positions indicated i. e. armaturer onto contact 6, armature 7 onto contact 7". At the commencement of the next revolution to be effected by the brushes 6 to I)", contacts at drums t t are again opened, so that the condensers [c and 7: are now in the position to store up the next signal arriving in the course of this revolution across the main L. In the further course of this revolution, the signal already set at the relay contacts 6 and f is printed. In. the example under consideration, this is done as soon as the brush glides across the segment o of the ring'S, while simultaneously the brush 6* glides across the segment o of the ring S \Vhile the said brushes pursue the path. described, the following fiow of current exciting the printing magnet D' is caused to take place: from. battery 15 across the printing magnet D, the relay armature r contact 7' segment '0 of the ring S brush Z2 conductor 0, brush b segment v contact 6 relay armature T and back to battery. The magnet D consequently attracts its armature q, and thus causes that type among the four types .2 of

the wheel T, which corresponds to the impulse combination -1, to be printed on the tape P.

For practical purposes and to render it possible to translate a larger number of signals, the arrangement may, of course, be suitably multiplied. It will also prove expedient not to charge the condensers directly with the line currents, but to efiect this in a local circuit with the aid of a special line relay for the receiver, which is not shown here since it forms no part of the present invention.

I claim 1. In a receiver for type-printing telegraphs in which the signal to be printed is composed of a plurality of line current impulses, in combination a distributor con sisting of a moving element connected to the line and contact segments equal in num' her to the number of impulses composing a signal, condensers each connected to one of said segments, relays equal in number to that of the condensers and each connected to the other side of one of said condensers, a switching device adapted to mechanically coact with the moving element of said distributor and electrically connected to said relays and condensers to cause their connection in circuit with each other when no line impulses are transmitted to said condensers, and a printing mechanism electrically controlled by the armatures of said relays.

2. In a receiver for type-printing telegraphs in which the signal to be printed is composed of a plurality of line current impulses, in combination a distributor consisting of a moving element connected to the line, and contact segments equal in number to the number of impulses composing a signal, condensers each connected at one side to one of said segments and all having their other side connected in common, relays equal in number to that of said condensers and having one of their terminals connected to said common sides of the condensers, a switching device adapted to mechanically coact with the moving element of said distributor and having electrical connections with the other terminals of said relays and with the other, not common, sides of said condensers, to cause the connection of said condensers and relays in circuit with each other when no line impulses are transmitted to said condensers, and a printing mechanism electrically controlled by the armatures of said relays.

In testimony whereof I aflix my signature.

ERVVIN EHRHARDT. 

